Segment Reporting (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Segment Reporting Information [Line Items]
Net operating income	$ 144,661	$ 137,893
Development and management services income	8,149	7,428
Income from unconsolidated joint ventures	11,721	7,976
Interest and other income	1,646	974
Gains from investments in securities	801	373
Gains from early extinguishments of debt	767
Gain on forgiveness of debt from discontinued operations	17,807
General and administrative expense	27,619	24,643
Transaction costs	2,104	72
Depreciation and amortization expense	109,673	109,237
Interest expense	103,237	98,525
Loss from discontinued operations	156	497
Noncontrolling interest in property partnerships	546	529
Noncontrolling interest-redeemable preferred units of the Operating Partnership	801	823
Noncontrolling interest-common units of the Operating Partnership	6,089	6,090
Noncontrolling interest in discontinued operations-common units of the Operating Partnership	1,942	(61)
Net income attributable to Boston Properties, Inc.	64,632	40,813
Business Intersegment, Eliminations [Member]
Segment Reporting Information [Line Items]
Net operating income	275,908	264,417
Development and management services income	8,149	7,428
Income from unconsolidated joint ventures	11,721	7,976
Interest and other income	1,646	974
Gains from investments in securities	801	373
Gains from early extinguishments of debt	767
Gain on forgiveness of debt from discontinued operations	17,807
General and administrative expense	27,619	24,643
Transaction costs	2,104	72
Depreciation and amortization expense	109,673	109,237
Interest expense	103,237	98,525
Loss from discontinued operations	156	497
Noncontrolling interest in property partnerships	546	529
Noncontrolling interest-redeemable preferred units of the Operating Partnership	801	823
Noncontrolling interest-common units of the Operating Partnership	6,089	6,090
Noncontrolling interest in discontinued operations-common units of the Operating Partnership	1,942	(61)
Net income attributable to Boston Properties, Inc.	$ 64,632	$ 40,813